In order to transmit torque from an onboard taxi system to a main wheel, there needs to be some form of drive gear or similar mechanism that connects the wheel to the transmission. However, aircraft wheels and axles flex considerably due to the loads imposed on them by aircraft operations on the ground. This flexing of the wheel and its interconnection with the aircraft makes it quite difficult to connect the wheel to the essentially rigid structures of the transmission and its drive gear. Such interconnection necessarily imposes significant stresses into the meshing gear interface unless appropriate design considerations are implemented.
In addition to managing the flexible-to-rigid structural transition, a design for the drive mechanism for an onboard taxiing system must not interpose an adverse impact on space utilization. Moreover, the structure and method of achieving the onboard taxiing system must have minimal impact on the critical thermal performance of the associated wheel and brake assembly. Accordingly, applicants have determined that the design should not obstruct airflow to and from the wheel, allowing ventilation to be maximized.
It has also been determined that since the taxi-drive interface will necessarily need to be connected and disconnected frequently whenever a wheel needs to be removed and reinstalled, this interface needs to minimize any maintenance burden.